We measured the effects of angiotensin II blockade on arterial stiffness, augmentation index (AI%), pulse wave velocity (PWV), and blood pressure (BP) in 12 hypertensive patients (mean 49 +/- 11 years) in a 4-week, randomized, cross-over study comparing valsartan 160 mg/day with captopril 100 mg/day, with a 2-week washout period. Subsequently both therapies were combined. Reductions in PWV and AI% remained significant when corrected for BP. Combined therapy reduced PWV and AI% (P < .05) more than monotherapy, even when corrected for BP. The study shows that angiotensin receptor antagonists reduce arterial stiffness in hypertension comparable with and possibly additive to angiotensin converting enzyme inhibition.